What can I say in a 3 minute speech on "In order to achieve true freedom we have to be free from vices?"

To some philosophers, this statement is absolutely true. 
They argue that all vices tend to enslave people.  They say that when we indulge our
vices, we are letting our desires control us and are not truly free.  In order to speak
on this, you should introduce this idea to your listeners and then give examples that
tend to support it.

The clearest examples of how this is
true come from various sorts of addictions or compulsions.  Smoking is one example. 
Many people who smoke are addicted to nicotine and can therefore not stop smoking.  They
lack true freedom because they cannot decide for themselves (not easily, at least)
whether to smoke or not.  For some people, overeating is the same way.  They know they
shouldn't overeat, but have a very hard time abstaining.  This, too, seems like a lack
of freedom.

So, to do this speech, introduce the idea that
indulging in vices allows your (generally physical) desires to control you.  It is only
if you get rid of vices that your free will is in control.  This is the essence of
freedom since you are able to choose what you do.  Then give examples that you can think
of that support the idea.